Motivated by the above discussions, in this work we investigate the RIS assisted communication system by designing a configuration with integrated sensing capability. The main advantage of the considered system is that with the aid of current communication network the sensing can be introduced by adding dedicated sensing processing from received communication signals, which averts the extra deployment of sensory networks. One typical example is the perceptive mobile network [1]}, [2]}, which evolves from the current communication-only mobile network. It is expected to serve as a ubiquitous radar-sensing network, whilst providing uncompromising mobile communication services.
Specifically, we propose a new RIS-aided ISAC scenario, where a BS not only communicates with multiple devices (such as vehicles) in full-duplex, but also senses the positions of these devices simultaneously. We assume that an RIS is mounted on each device to enhance the echoes reflected by the device. Meanwhile, the information of each device is passively transferred to the BS via reflection modulation [3]}, [4]}, in which the information is encoded into the phase adjustments of RIS meta-atoms. The proposed ISAC scenario is advantageous in two aspects. First, the communication system is full-duplex in frequency and time, where the information delivered by the BS can be received by the devices using conventional receivers, and, at the same time/frequency slot, the information of the devices is passively delivered to the BS via reflection modulation thanks to the RISs. Second, the devices are “green” since they do not emit any electromagnetic signals during the whole process.
